Japanese Patent No. 3017770 discloses a medical apparatus as a first conventional art for magnetically guiding in a sample.
According to the first conventional art, the medical apparatus comprises a guided portion which is magnetically guided at least to a part of an inserting portion inserted in the sample, and moving means which moves magnetic force generating means arranged out of the sample in the direction that balances in the one guided direction and in the direction that cannot control the balance.
Further, Japanese Patent No. 3017770 discloses a method for magnetically guiding a general endoscope inserting portion or a capsule endoscope. Furthermore, Japanese Patent No. 3017770 discloses a method for vibrating the endoscope inserting portion by an AC magnetic field and rotating and guiding the capsule endoscope.
Japanese Unexamined Patent Application Publication No. 2001-179700 discloses a medical apparatus which comprises a magnetic field generating unit which generates a rotating magnetic field, and a robot main body which receives the rotating magnetic field and obtains the thrust, wherein the surface of the rotating magnetic field can be changed in a predetermined direction in the three-dimensional space.
As disclosed in Japanese Unexamined Patent Application Publication No. 2001-179700, as a thrust generating unit, mechanical means such as a spiral or a screw suitable to the advance in the fluid is arranged to the robot main body and a drill unit is arranged to the front end and rear end of the robot main body so as to be movable if a solid material or gel material exists in the advance direction.
However, the first conventional art has the following problems.
That is, the magnetic force generating means out of the sample must be moved in accordance with the direction for guiding the guided portion. Therefore, the moving means arranged outside the body has the complicated structure and the control operation. Hence, the body cavity inserting portion does not stably advance in the body cavity.
Further, the capsule endoscope does not have the thrust generating unit for converting rotating force into the thrust on the outer surface. Therefore, the lost motion is caused in the body cavity in many cases and the stable thrust is not obtained.
Moreover, according to the second conventional art, the body cavity inserting portion in the medical apparatus receives the rotating magnetic field and the stable advance in contact with the inner wall in the body cavity are not considered. Therefore, if the disclosed contents are directly applied, the following problems are caused.
(a) The shape of the thrust generating unit (spiral, screw, or drill) is not optimal and therefore the lost motion is caused in a non-contact state with the inner wall in the body cavity. If the contact state is realized, the thrust speed is slow per rotation.
(b) The optimal magnetic torque is not considered and therefore the torque is not sufficiently obtained, or the magnetic torque more than necessary is obtained but an extra-body device is increased in size.
Therefore, the present invention is devised in consideration of the problems of the first and second conventional arts and it is one object of the present invention to provide a medical apparatus, in which the body cavity inserting portion stably advances in contact with the inner wall in the body cavity by receiving the rotating magnetic field.
It is another object of the present invention to provide a medical apparatus having the thrust generating unit which is optimal for the body cavity inserting portion to stably advance in the body cavity.
It is another object of the present invention to provide a medical apparatus, in which it is possible to generate and arbitrarily set the magnetic torque that is optimal for the body cavity inserting portion to stably advance in the body cavity.